When creating pastes with the web UI, they end up with CRLF line endings. Example:
$ wget https://paste.sr.ht/blob/d07cff009c449bfdf131d865e1dc4413256e5f52 [...] $ file d07cff009c449bfdf131d865e1dc4413256e5f52 d07cff009c449bfdf131d865e1dc4413256e5f52: ASCII text, with CRLF line terminators
When you submit a form the standard requires the data is separated by CRLF: https://www.w3.org/TR/2018/WD-html53-20181018/sec-forms.html#plain-text-form-data
I guess the CRLF could be converted to LF which is what services like Github does.